Electrode for lithium-ion secondary battery and manufacturing method thereof, and lithium-ion secondary battery

Abstract

A highly reliable electrode for a lithium-ion secondary battery is provided. A highly reliable lithium-ion secondary battery is also provided using the electrode for a lithium-ion secondary battery. The electrode for a lithium-ion secondary battery includes a current collector and an active material layer. The active material layer includes an active material, graphene, and polyimide. The active material includes a plurality of nanowires each of which grows with a silicon particle used as a nucleus and extends in one direction into a fine needle. The graphene includes a region in contact with the plurality of nanowires, and polyimide includes a region in contact with the graphene. The lithium-ion secondary battery uses the electrode as a negative electrode.

What is claimed is: 
     
       1. A method for manufacturing a lithium-ion storage battery comprising:
 providing a negative electrode adjacent to a positive electrode, 
 wherein the positive electrode comprises a positive electrode current collector and a positive electrode active material layer, 
 wherein the negative electrode comprises a negative electrode current collector and a negative electrode active material layer, 
 wherein the negative electrode active material layer comprises silicon particles and a binder, 
 wherein a silicon wire is formed from a first part of the silicon particles by heating after forming the negative electrode active material layer, 
 wherein the silicon particles have an average diameter of 10 nm to 1 um before the heating, and 
 wherein a thickness of the negative electrode active material layer is smaller than a thickness of the positive electrode active material layer. 
 
     
     
       2. A method for manufacturing a lithium-ion storage battery comprising:
 providing a negative electrode adjacent to a positive electrode, 
 wherein the positive electrode comprises a positive electrode current collector and a positive electrode active material layer, 
 wherein the negative electrode comprises a negative electrode current collector and a negative electrode active material layer, 
 wherein a method for manufacturing the negative electrode active material layer comprises:
 mixing a first mixture comprising silicon particles and graphene oxide, a polyimide precursor and a solvent to form a slurry; and 
 applying the slurry over the negative electrode current collector and heating, 
 
 wherein the heating forms a nanowire using a first part of the silicon particles, reduces the graphene oxide to graphene, and imidizes the polyimide precursor to polyimide, and 
 wherein the nanowire grows with a second part of the silicon particles used as a nucleus and extends into a needle by the heating. 
 
     
     
       3. The method for manufacturing the lithium-ion storage battery according to  claim 1 ,
 wherein the binder is polyimide, 
 wherein a precursor of polyimide is used for forming the negative electrode active material layer, and 
 
       wherein the precursor of polyimide is imidized by the heating. 
     
     
       4. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the silicon wire has a length of ten micrometers or more. 
     
     
       5. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein a second part of the silicon particles forms a first aggregated object by the heating. 
     
     
       6. The method for manufacturing the lithium-ion storage battery according to  claim 5 , wherein the silicon wire grows with the first aggregated object as a nucleus. 
     
     
       7. The method for manufacturing the lithium-ion storage battery according to  claim 6 ,
 wherein a third part of the silicon particles forms a second aggregated object by the heating, and 
 wherein the silicon wire is attached to the second aggregated object after the heating. 
 
     
     
       8. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the heating is performed at a temperature equal to or less than 400° C. 
     
     
       9. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the heating is performed at a temperature equal to or greater than 360° C. and equal to or less than 400° C. 
     
     
       10. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the negative electrode active material layer comprises a conductive additive. 
     
     
       11. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the negative electrode active material layer comprises graphene and polyimide. 
     
     
       12. The method for manufacturing the lithium-ion storage battery according to  claim 1 , wherein the positive electrode active material layer comprises graphene and polyvinylidene fluoride. 
     
     
       13. The method for manufacturing the lithium-ion storage battery according to  claim 2 , wherein a thickness of the negative electrode active material layer is smaller than a thickness of the positive electrode active material layer. 
     
     
       14. The method for manufacturing the lithium-ion storage battery according to  claim 2 , wherein the silicon particles have an average diameter of 10 nm to 1 μm before the heating. 
     
     
       15. The method for manufacturing the lithium-ion storage battery according to  claim 2 , wherein the nanowire has a length of ten micrometers or more. 
     
     
       16. The method for manufacturing the lithium-ion storage battery according to  claim 2 , wherein the heating is performed at a temperature equal to or greater than 360° C. and equal to or less than 400° C. 
     
     
       17. The method for manufacturing the lithium-ion storage battery according to  claim 2 , wherein the positive electrode active material layer comprises graphene and polyvinylidene fluoride.